Rear Side-Impact Airbags; Mrs Deployment Logic - BMW 1999-2005 M3 Service Manual

Airbag System (SRS)
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Upon severe side impact, a gas
generator unit fills the Head Protection
System (HPS) tube with inert gas. The
expanding tube pops out of the trim to
form a straight tube 5.1 inches in
diameter and stretched in a straight line
from the lower windshield pillar to above
the rear door. The inflated tube is
located to prevent the front occupant's
head from contacting the A-pillar, the
B-pillar, or side window. The tube's
sloping position allows protection for
both short and tall people. The inflated
tube is stiff enough to retain much of its
effectiveness even if the window is
broken. The HPS tube remains inflated
for approximately 7 to 8 seconds to
extend protection time in case the
vehicle encounters additional side
impacts during the crash.

Rear side-impact airbags

Similar to the standard-equipment front
side-impact airbags, the rear airbags are
built into the doors of sedan models.
These were offered as a special order
option on certain models only. They can
be deactivated to protect infants or small
children riding in the rear seat. Activation
and deactivation can be performed by
using either DIS or MoDiC BMW scan
tools.

MRS deployment logic

Main sensing and triggering functions for
the front-impact airbags and seat belt
tensioners are combined into a single
MRS control module located above the
center tunnel, under the rug, beneath
the parking brake handle.
Side-impact and head protection airbags
are controlled by separate sensors, one
for each side of the vehicle.
2/25/2009 11:21 PM